To quickly re-set the table, my organization purchased the Oracle ZFS Storage Appliance (ZFSSA) 7420. Oracle sold us on the Infiniband connectivity as a way to make a possible future transition to Exadata easier. However the pre-sales (more...)
Note: The following is based on testing with 22.214.171.124 (I believe same issue exists within other Oracle versions).
I recently worked on an interesting problem relating to the “enq: TX – contention” wait event. There are a number of reasons for the wait but the most common (more...)
My site uses a 3rd party SQL monitoring tool which collects data based on the Oracle view v$sqlstats. The tool collects data for all sql statements which have been executed since the previous collection using the last_active_time column. A few months ago we noticed (after an upgrade to 11g) we (more...)
I just stumbled upon this bug reference on My Oracle Support:
Bug 13262857 Enh: provide some control over DBMS_STATS index clustering factor computation
This enhancement was long due. Previously, when computing the clustering factor during gathering statistics, the value was incremented, whenever the row was not found in the same block as the previous row. Now, it is finally possible to determine how many blocks should be considered when computing clustering factor. The patch delivers an improved DBMS_STATS package body that can be used to set preferences with value TABLE_CACHED_BLOCKS.
The flaw in the over-simplistic and pessimistic original computation was (more...)
I recently investigated an IO performance “spike” on a large 126.96.36.199 transactional system and I thought I would cover some interesting issues found. I am going to take the approach of detailing the observations made from our production and test systems and avoid attempting to cover how other versions of Oracle behave. The investigation also uncovers a confusing database statistic which we are currently discussing with Oracle Development so they can decide if this is an Oracle coding bug or a documentation issue.
The initial IO issue
We run a simple home grown database monitor which watches database wait events and sends an email alert if it detects either a (more...)
We need to follow the
I’ve seen some posts on the blogosphere where people attempt to explain (or should I say guess) how Exadata Smart Flash Logging works and most of them are wrong. Hopefully this post will help clear up some the misconceptions out there.
The following is an excerpt from the paper entitled “Exadata Smart Flash Cache Features and the Oracle Exadata Database Machine” that goes into technical detail on the Exadata Smart Flash Logging feature.
Smart Flash Logging works as follows. When receiving a redo log write request, Exadata will do
parallel writes to the on-disk redo logs as well (more...)
Just a quick note to say that RedHat submitted certification test result of Oracle 11gR2 on RHEL6 to Oracle Corporation on 09-Aug-2011, so we should expect the formal certification around last week of Sep-2011.
Oracle has finally certified 11gR2 on OEL6 and RHEL6. See the announcement here
Filed under: 11gR2, Linux, Oracle
[root@host1 bin]# ocrcheck Status of Oracle Cluster Registry is as follows : Version : 3 Total space (kbytes) : 262120 Used space (kbytes) : 3004 Available space (kbytes) : 259116 ID : 798462606 Device/File Name : /mnt/cludata/ocrfile Device/File integrity check succeeded Device/File not configured Device/File not configured Device/File not configured Device/File not configured Cluster registry integrity check succeeded Logical corruption check succeeded2.) Add a Mirror OCR (more...)
I was going to write a new post about change in behaviour of Guaranteed Restore Point and Flashback mode. But looks like someone has already written about it at given below link. Its seems behaviour has changed in 11gR2, but documentation still refers to old behaviour.
I have raised a Oracle Service Request to correct the documentation. Documentation Bug – 12763133.
Filed under: 11gR2, Backup, Flashback, Oracle